Controlled refrigerating apparatus with secondary refrigerating circuit



Dec. 23, 1947.

c. FQALSING 7 CONTROLLED REFRIGERATING APPARATUS WITH SECONDARYREFRIGERATING CIRCUIT Filed May 25, 1945 2 Sheets-Sheet l F'za iWITNESSES:

m INVENTOR CARL F. ALsma AITORNEY Dec. 23, 1947. I c, F, ALslNG2,433,187

CONTROLLED REFRIGERATING APPARATUS WITH SECONDARY REFRIGERATING CIRCUITFiled May 25, 1945 2 Sheets-Sheet 2 WITNESSES: INVENTOR i CARL. F.RLSING. 6 7 FIG. 3. WM

ATTORNEY Patented Dec. 23, 1947 CONTROLLED REFRIGERATING APPARA- I TUSWITH SECONDARY REFRIGERATING CIRCUIT Carl F. Alsing, Wllbraham', Masa,asslgnor to Westinghouse Electric Corporation, East Pittsburgh, Pa., acorporation of Pennsylvania Application May 25, 1945, Serial No. 595,810

11 Claims. (Cl. 62-2) This invention relates to refrigerating apparatuscomprising a secondary volatile refrigerant circuit and more especiallyto a means ior controlling the secondary circuit,

Modern domestic refrigerators provide a compartment for storing frozenfoods and a second compartment for ordinary refrigerated storage. Eachof these compartments is preferably maintained at a constant temperaturein spite of variations in the room temperature.

It is, accordingly, an object of this invention to provide novel andsimple means for maintaining two refrigerated compartments at-diiferentbut relatively constant temperatures in spite of variations in the roomtemperature in which the compartments are located.

A further object of the invention'is to provide novel means forcontrolling a secondary volatile refrigerant circuit-to providepredetermined temperatures in a chamber'in response to changes in theambient temperature of the chamber.

These and other objects are effected by the invention as will beapparent from the following description and claims taken in connectionwith the accompanying drawings forming a part of this application, inwhich:

Fig. 1 is a vertical section of a mechanicallycooled refrigeratorembodying the invention;

Fig. 2 is a front elevation of the food storage chamber of therefrigerator with the door open;

Fig, 3 is a sectional view of the controlling vesg sel of thisinvention; and

Fi 4 shows a modification of the invention in which thetemperature-sensitive tube is located on the outer metal shell of thecabinet.

Referring now to the drawings for a detailed description of theinvention, the reference numeral 6 designates a refrigerator cabinethaving an insulated food storage chamber 1 in the upper portion thereofand a machinery compartment 8 below the food storage chamber I. The foodstorage chamber I comprises an outer metal shell 9. a metal. food linerI therein, and heatinsulating material ll packed between the outer shell9 and the food liner It. A partition II divides the food chamber intotwo compartments, the u per compartment is being devoted to the storageof frozen foods and maintained at a temperature of about F. and thelower compartment l5 being devoted to the storage of comestibles atabout 40 F.

The upper compartment I 4 is refrigerated by a mechanical refrigeratingapparatus which hereafter will be designated as the primary apparatus.

- It comprises a primary evaporator I! which supplied through acapillary tube I 8 with a volatile liquid refrigerant and therefrigerant vaporis withdrawn from the evaporator 16 by a suction tube20. The suction tube 20 connects with a sealed housing 22 containing a.refrigerator compressor and a. motor for driving the same. The motor andthe compressor are not shown in the drawings. Compressed refrigerant isconducted from the compressor to a primary condenser 24 1. through atube 28. The lower end of'the condenser 24 connects with the capillarytube It.

The temperature of the primary evaporator It is controlled by athermostat 30 shown diagrammatically in the drawings. The thermostat 30cflmprises a bulb 32 containing a volatile liquid, the vapor pressure ofwhich is transmitted to a metal bellows 34 which actuates a switch it.The

' switch 38 controls the operation of the motor in termined temperatureand closes when the evaporator l6 warms up to another predeterminedtemperature. The thermostat thus provides that the evaporator .IB ismaintained between predetermined temperature limits so that its averagetemperature remains constant in spite of variations in the-temperatureof the room in which the cabinet III is located. The foods stored in thecompartment it will be at a substantially condisa stant temperaturebecause of the thermal storage capacity of the foods.

The lower compartment I is cooled by a volatile refrigerant circuit 40which hereafter will be re- The secondary refrigerant circuit 40comprises a secondary evaporator consisting of a tube 44 located inheat-exchange relationship with the metal food liner III of the lowercompartment IS. The secondary refrigerant circuit 40 also comprises asecondary condenser comprising a tube located in heat-exchangerelationship with the evaporator It. The tubes ,44 and 50 areinterconnected.

. e refrigerating apparatus, as thus far dese d, is well known in theart but has the antage that the temperature of the lower com-j rtment Ivaries with the temperature of the room in which the refrigerator islocated. The refrig ator of this invention corrects this defect byrendering the secondary refrigerant system less effective when the roomtemperature is low than when it is high, by varying the quantity ofrefrigerant which circulates in the secondary circu t.

To accomplish this result, a vessel 58 is located in the secondarycircuit 48 below the condenser 50 to receive the condensate therefrom.Spaced from the bottom of the vessel 58 is an opening 80 whichcommunicates with the secondary evaporator 44 so that the refrigerantliquid will drain into the evaporator 44 after the vessel 88 is filledto the level of the opening 68. The opening 60 thus constitutes aspillway.

A metal bellows 82 is located in the vessel-58 below the level of theopening 68 and communicates through a tube 84 with a bulb 86 located inheat-transfer relationship with the condenser 24. The space between thewalls of the vessel 58 and the bellows 82 forms a storage tank 61 ofvariable capacity for the refrigerant liquid. A coiled spring 68 in thevessel 58 biases the bellows 82 to its contracted position. The bellows62, tube 64, and a portion of the bulb 66 are filled with a volatileliquid 59 so that, during operation of the refrigerator, the pressure ofthe fluid is dependent on the temperature of the bulb G6.

The refrigerant charge in the secondary circuit 40 is such that when thebellows 62 is contracted, substantially all of the refrigerant liquidwill accumulate in the tank 81 during operation.

Operation The operation of the device is as follows: When the roomtemperature increases and also when warm foods are placed in the storagechamber I, the refrigerating apparatus will operate for a larger portionof the total time than previously and the condenser will assume a highertemperature. This temperature is transmitted to the bulb 68, and thevapor pressure of the liquid 59 therein will increase and expand thebellows 62. The bellows, on expanding, drives more of the refrigerantliquid into the secondary circuit 40 and increases its effectiveness intransferring heat from the inner liner ID of the food storagecompartment l to the primary cooling unit it.

As the temperature ambient the refrigerator decreases, the oppositeaction occurs, namely, the condenser 24 will run at a lower temperatureand for less time, the bellows 62 will contract so that alarger portion,or in an extreme case, the entire secondary refrigerant charge will belocated in the tank 61 and little or none will be available fortransferring heat from the liner I of food storage compartment 1 to theprimary evaporator 16.

The quantity of the liquid displaced in the vessel 58 is preferably soproportioned to the heat leakage of the lower compartment 1 that thetemperature of the latter remains constant in varying room temperatures.However, it may also be proportioned to vary the temperature of thecompartment 'l with changes in the ambient temperature of therefrigerator. Thus, the temperature of the compartment 1 can be made torise or to fall in response to a rise in the ambient temperature.

Modification refrigerator and thus responds mainly to room temperature.The action is similar to that of the previously described modificationwith the exception that placing warm foods in the storage chamber I onlyremotely affects the action of the secondary circuit 48. In thismodification, the temperature variations to which the bulb is subjectedare not as great as in the previously described modification, so that amore sensitive spring 68 is required. In either modification, the spring68 may be eliminated if the bellows 82 has an inherent tendency tocontract.

It will be apparent from the above that this invention provides a simplemeans for maintaining two refrigerating compartments at different butrelatively constant temperatures in varyin room temperatures. It alsoprovides a novel means for controlling a secondary volatile refrigerantcircuit without introducing valves or other movable parts in thecircuit.

While the invention has been shown in several forms, it will be obviousto those skilled in the art that it is not so limited, but issusceptible of various other changes and modifications without departingfrom the spirit thereof.

What is claimed is:

1. In a refrigerator comprising a thermallyinsulated food storagechamber, a cooling means. a volatile refrigerant circuit for coolingsaid food storage chamber, said. refrigerant circuit including acondenser in heat-transfer relationship with said cooling means, a tankfor receiving liquid refrigerant from said condenser, said tank havingan opening spaced from the bottom thereof, an evaporator inheat-transfer relationship with said storage chamber and communicatingwith said opening to receive liquid refrigerant from said tank, andthermostatic means in heattransfer relationship with an element whichvaries in temperature in response to the ambient temperature of saidchamber for decreasing the refrigerant volume of said tank below thelevel of said opening when said ambient temperature increases and forincreasing said volume when said ambient temperature decreases.

2. In a refrigerator comprising a thermallyinsulated food storagechamber, a primary cooling means maintained at a constant average tem--perature for cooling a portion of said chamber, a secondary volatilerefrigerant circuit having an evaporative portion for cooling anotherportion of said food storage chamber and a condensing portion inheat-transfer relationship with said primary cooling means, thecombination with said refrigerator of a control for said secondarycircuit, said control comprising a tank in said circuit located belowthe condensing portion to receive liquid refrigerant therefrom, anopening in said tank spaced from the bottom thereof and communicatingwith said evaporative portion to" drain liquid refrigerant into saidportion, said control including a thermostat in heat-transferrelationship with an element which varies in temperature responsive tothe ambient temperature of said chamber for decreasing the volume ofsaid tank below the level of said opening when said ambient temperatureincreases and for increasing said volume when said ambient temperaturedecreases.

3. In a refrigerator comprising a thermallyinsulated food chamber, acooling means, a volatile refrigerant circuit for cooling said foodstorage chamber, said refrigerant circuit including a condensing portionin heat-transfer relationship with said cooling means, a tank adapted toreceive liquid refrigerant from said condensing portion, said tankhaving an opening spaced from the bottom thereof, an evaporative portioncommunicating with said opening to receive liquid, refrigerant from saidtank and thermostatic means responsive to the ambient temperature of therefrigerator for decreasing the volume of said tank below the level ofsaid opening when said temperature increases and for increasing saidvolume when said temperature decreases.

4. In a refrigerating system, comprising a cooling means, a volatilerefrigerant circuit for cooling an insulated'storage chamber, saidrefrigerant circuit including an evaporative portion in heat-transferrelationship with said food chamber, and a, condensing portion in heattransfer relationship with said cooling means, the combination with saidcircuit of a tank adapted to receive liquid refrigerant from saidcondensing portion, said tank having an opening spaced from the bottomthereof and communicating with said evaporative portion to transmitliquid refrigerant to the same, said tank having a movable wall to varythe volume of the portion of the vessel below the level of said opening,and a thermostatic element responsive to the ambient temperature of thestorage chamber to move said wall to. decrease the volume of saidportion of said tank when said temperature increases and for increasingsaid volume when said temperature decreases.

5. In a refrigerating system, comprising a cooling means, a, volatilerefrigerant circuit for cooling an insulated storage chamber, saidrefrigerant circuit including an evaporative portion in heat-transferrelationship with said food chamber, and a condensing portion inheat-transfer relationship with said cooling means, the combination withsaid circuit of a tank adapted to receive liquid refrigerant from saidcondensing portion, said tank having an opening spaced" from the bottomthereof and communicating with said evaporative portion to transmitliquid refrigerant to the same, said tank having a movable wall to varythe volume of the portion of the tank below said opening, refrigerantliquid in said secondary circuit equal in volume to the maximum volume"of said portion of saidtank; and a thermostatic element responsive tothe ambient temperature of the storage chamber to move said wall todecrease the volume of said portion of said tank when said temperatureincreases and for increasing said volume when said temperaturedecreases.

6. In'a refrigerator comprising a thermallyinsulated food storagechamber, a cooling means,

a volatile refrigerant circuit having an evaporative portion for coolingsaid food storage chamber and a condensing portion in heat-transferrelationship with said cooling means, the combination with saidrefrigerator of a control for said secondary circuit, said controlcomprising a tank in said circuit adapted to receive liquid refrigerantfrom said condensing portion, an opening in said tank spaced from thebottom thereof and communicating with said evaporative portion to drainliquid refrigerant into said evaporative portion, said control includinga thermostatic element comprising a' bellows in said tank positioned atleast in part below the level of said opening, a, bulb responsive to thetemperature ambient the refrigerator, a conduit connecting said bulb andbellows, and a volatile fluid in said thermostatic element to expand andcontract said bellows in response to the temperature of said bulb.

thereof, an evaporative portion communicating with said opening toreceive liquid refrigerant from said tank and a thermal elementassociated with said tank, said element comprising an expansible bellowslocated in said tank below the level of said opening, a bulb responsiveto the temperature ambient the food chamber, a tube connecting said bulband bellows, and a quantity of volatile liquid in said thermal element.to eifect expansion and contraction of said bellows in response to thetemperature of said bulb.

8. In a refrigerator comprising a thermallyinsulated food chamber, aprimary mechanical refrigerating unit including a primaryevaporator, acondenser cooledv by the ambient air of the food chamber. and means formaintaining said primary evaporator at a constant average temperature, asecondary volatile refrigerant circuit for cooling another portion ofsaid food storage chamber, said circuit including a condensing portionin heat-transfer relationship with said priinary evaporator, a tankcommunicating with said condensing portion to receive liquid refrigeranttherefrom, said tank having an opening spaced from the bottom thereof,an evaporative portion communicating with said opening to receive liquidrefrigerant from said tank and a thermostatic element responsive to thetemperature of said primary condenser for decreasing the volume of saidtank below the level of said opening when said temperature increases andfor increasing said volume whensaid temperature decreases. V

9. In a refrigerator comprising a food storage chamber having a metalplate forming at least a portion of the outer wall of said chamber andlocated in heat-transfer relationship with the air ambient the chamber,an inner liner spaced from said outer plate, and heat insulation betweensaid liner and plate, a cooling means, a volatile refrigerant circuitfor cooling said food storage chamber, said refrigerant circuitincluding a condensing portion in heat-transfer relationship with saidcooling means, a tank communicating with said condensing portion toreceive liquid refrigerant therefrom, said tank having an opening spacedfrom the bottom thereof. an evaporative portion'communicating with saidopening to receive liquid refrigerant from said tank and a thermostaticelement responsive to the temperature of said plate for decreasing thevolume of said tank below the level of said opening when saidtemperature increases and for increasing said volume when saidtemperature decreases.

10. A refrigerator comprising a thermally insulated food storagecabinet, a cooling means, a

volatile refrigerant circuit having substantially the same pressurethroughout, said circuit includ and thermostatic means responsive totheambient temperature of said cabinet for decreasing the liquid storagecapacity of said tank below said spillway when said ambient temperatureincreases and for increasing said liquid storage capacity when saidambient temperature decreases.

11. A refrigerator comprising a thermally in-.- sulated food storagecabinet, a cooling means, a volatile refrigerant circuit havingsubstantially the same pressure throughout, said circuit including acondenser in heat-transfer relationship with said cooling means, astorage tank for receiving liquid refrigerant condensed by saidcondenser, an evaporator for cooling said cabinet, means for conductingrefrigerant liquid from said tank to said evaporator, said meansincluding a spillway elevated above the bottom of said tank,thermostatic means responsive to the ambient temperature of'said cabinetfor decreasing the liquid storage capacity of said tank below saidspillway when said ambient temperature increases and for increasing saidliquid storage capacity when said ambient temperature decreases, and aquantity of refrigerant in said system such that all of the refrigerantliquid will accumulate in said tank when said circuit is in operationand said volume is at its maximum.

CARL F. ALSING.

REFERENCES CITED The following references are of record in the tile ofthis patent:

v v UNITED STATES PATENTS Number Name Date 1,974,121 Normelli Sept. 18,1934

